ISSN:
0030-493X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
From the standpoint of relative molecular mass (RMM) determination by mass spectrometry, the average relative molecular masses of organic molecules in the range over 2000 daltons are significantly influenced both by the fractional masses of the constituent elements and by natural variations in isotopic abundance. Differences between monoisotopic RMM and relative atomic mass (RAM) based RMM tend characteristically to differ between major classes of biomolecules primarily because of molar carbon content, the difference between polypeptides and nucleic acids being about 4 daltons at Mr = 25 000. Considering terrestrial sources alone, variations in the isotopic abundance of carbon lead to differences of about 10-25 ppm in average molecular mass, which is significant with respect to present mass measurement capability in the region up to several thousand daltons. Comments are made concerning the calculation of average RMM values horn isotopic probability profiles versus those from RAMs.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/oms.1210220505
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